If we include other media there's a lot more prominent trainers using psedo legends
- Iris has Dragonite in the anime. Alexandra has one in Rejuvenation, and it's probably Sapphira's ace
- Colress has Metagross in BW2's postgame (and he can mega evolve it in the Battle Tree). Radomus uses one during both battles in Reborn
- Heather has a Salamance, and its presumably her ace. Kanon also had one in Rejuvenation
- Wally gets a Garchomp in ORAS postgame. Its also Terra's ace in Reborn
- Melia, Damien, and Dr Isha all have Hydreigon in Rejuvenation. And of course its Lin's ace
- Zinnia and Raihan both use Goodra
- Cynthia has a Kommo-o in the anime and Masters
- Geara, Dr Isha, and protagonist Ana all use Dragapult in Rejuventaion (tho only on Intense mode)
As for Tyranitar, I can't name any other major trainers that use it, and Luna didn't even use hers in the Glass Gauntlet. Kinda seems like its getting the short end of the stick